![LITERARY REVIEW OF INTERBODY CAGES IN SPINALSURGERY 10
do not discuss if the Viswanathan series used the posterior or anterior approach in the patients
studied due to neurological indications.
Neurological deficit correction, as with other study outcome variables, was published in
all three articles at the pre-and postoperative periods and during follow-up, using various scoring
instruments. Data from the Wang series were measured utilizing the ASIA Impairment Scale,
(Table 1.). Viswanathan used the Frankel scale in his study, whereas Twenty-seven patients
(28%) presented preoperatively with neurological deficit. [Frankel grade A (N = 2), C (N = 13)
or D (N = 12)]. Postoperatively, one patient with a Frankel grade A was a E at discharge. The
remaining 18 patients remained stable. Kocis’s case study of a single patient gives a clinical
assessment. His 25 year-old 5th lumbar fracture patient presented at the time of emergency
surgery with unspecified neurological deficit. Kocis reported the patient remained stable, = 4
years postoperatively.
Postoperative Outcome
When discussing any type of surgical procedure, postoperative outcome is probably the
most important aspect of any intervention. And, in spinal surgeries, postoperative complications
can be severe and varied. However, in reviewing the three articles, the authors appear to be in
agreement that the interbody cage is a safe option for the correction of spinal trauma. Of the 124
patients from the three articles combined, postoperative complications overall occurred in 31
(25%) of all patients. The articles showed overlap in the type of complications seen, thus lending
some predictability to possible outcome.
Of patients reviewed by Viswanathan, 1 (0.8%) patient mortality due to a pulmonary
embolism occurred out of the 124 patients reviewed from the three articles combined. This
patient, from the post-vertebrectomy tumor group, had an intraoperative durotomy, then](https://image.slidesharecdn.com/82ab5f0c-6080-45aa-b5c8-c205b68b4d88-160102181025/85/GOODAY-ARTICLE-Final-10-320.jpg)
GOODAY.ARTICLE.Final
- 1. LITERARY REVIEW OF INTERBODY CAGES IN SPINALSURGERY 1 Interbody Spinal Cages as Vertebral Body Replacements and Support in Patients with Compromised Spinal Column due to Trauma or Disease Process. Peggy Gooday Example Article December 24, 2015 501 S. Spring Street, #324 Los Angeles, CA 90013 213-884-7529
- 2. LITERARY REVIEW OF INTERBODY CAGES IN SPINALSURGERY 2 Abstract In patients with spinal cord tumors and traumatic spinal cord injuries, the vertebral body may require reconstruction for stability, control of neurological damage and pain control. This article will review two case Studies and one retrospective series in the use of two types of interbody cages: the stackable cage, and the expandable titanium cage. A secondary issue to the decision to use the interbody cage is the surgical approach. The posterior v. anterior approach in spinal surgery and the functional outcome will also be reviewed. Keywords: Lumbar spine. Burst fracture. Posterior surgery. Expandable cage. Vertebrectomy. Metastatic spine tumor. Expandable titanium cage. Spine. Tumor. Reconstruction. Lumbar spine. Burst fracture. Posterior surgery. Stackable cage. Literary review.
- 3. LITERARY REVIEW OF INTERBODY CAGES IN SPINALSURGERY 3 There are several approaches to treating spinal column deformity, fracture, and neurological deficit present with severe trauma of the spine. This article review will examine two methods in the use of the interbody cage as a vertebral body replacement in the case of post- vertebrectomy patients having primary or metastatic tumors of the spine, and post-trauma patients requiring either spinal stability or correction of kyphotic spinal deformity, with or without neurological deficit. Within the confines of this subject of differing approaches to spinal column surgery, a second approach to which surgery is conducted shall also be explored in the utilization of the posterior approach for the placement of the intervertebral cage. Correction of Kyphotic Deformities in Patients with Spinal Trauma or Spinal Tumors Regardless of the means in which the spinal cord can become compromised, the necessary treatment goals are similar: to maintain spinal stability, increase quality of life (pain alleviation and mobility), and correction of deformities. In the article “Initial experience with the use of an expandable titanium cage as a vertebral body replacement in patients with tumors of the spinal column: a report of 95 patients” by Viswanathan et al, a retrospective review of 95 post-vertebrectomy patients with either primary (n-23), or metastatic tumors (n=72), assesses the safety and efficacy of use of an expandable titanium cage, (ETC), as a reconstructive device. In doing so, the goal is not only in stabilizing the spinal column to correct deformity and thus protect neurological function, but in the case of using the expandable titanium cage in metastatic tumor patients, also serves as a palliative measure in alleviating pain and maintaining functional independence. For patients with primary tumors, the use of the ETC can actually serve as a
- 4. LITERARY REVIEW OF INTERBODY CAGES IN SPINALSURGERY 4 curative measure. Satisfactory reports with regard to clinical outcome and rating scores, radiographic outcome, and post-operative complication rates support the author’s favorable report in the use of ETC in the surgical management of primary and metastatic spinal cord tumors. In a retrospective case series of twenty-seven post-trauma patients by Wang et al, “Correction of Late Traumatic Thoracic and Thoracolumbar Kyphotic Spinal Deformities Using Posteriorly placed Intervertebral Distraction Cages”, the article reports on two types of the interbody cage: the Radiolucent carbon-fiber reinforced polymer carbon-fiber stackable cage (Ocelot, DePuy Spine, Johnson & Johnson Co., Raynham, MA), and the Telescopic Synex expandable cage (SYNTHES, Paoli, PA). A second variable of this study is the surgical use of the posterior-only approach in a single operation, with satisfactory results. It appears that there is some debate as to which surgical approach is best, the posterior, anterior or posterior/anterior method, or if treatment only is a good option. According to Wang’s findings, results in using both cages to correct spinal cord deformity and in stabilization of neurological deficit, were favorable in sagittal correction, post-operative complications, and neurological stability. Supporting Wang’s article, a single patient case study of the serious spinal trauma with neurological deficit of a twenty-five year old male titled, “Complete burst fracture of the fifth lumbar vertebra treated by posterior surgery using expandable cage” by Kocis et al, describes the successful use of the posterior approach to surgical treatment for the burst fracture of fifth lumbar vertebra consisting of reduction, decompression, transpedicular stabilization fusion, post- surgery instrumentation and an expandable cage. The patient’s outcome was reported as good, with the patient remaining post-operatively problem free other than back pain, with no sign of
- 5. LITERARY REVIEW OF INTERBODY CAGES IN SPINALSURGERY 5 failure in the fixation. The patient walks with crutches and uses peroneal bands to overcome muscle palsy, as neurological deficit remains unchanged post-operatively. Methodology All three articles review safety, functional outcome, durability of reconstruction and post- operative complications in the placement of either the ETC or the stackable cage. Inclusionary criteria for all studies included kyphotic deformity, neurological deficit, and in the case of the tumor patients, post-vertebrectomy combined with the aforementioned clinical presentations. All of the reviews were retrospective, so none were controlled. The age range of the three studies combined had a median age of 54 years (range 20-84), so, given the variation of traumatic events leading to surgery, fortunately, there was a wide age- range to assess. All study patients, with the exception of Kocis’ case study of a single patient which occurred under emergency circumstance, were preoperatively assessed for kyphotic deformity using standard measurements, visual analog pain score, and neurological deficit. In combining all patients from the three reviews, (n=124), all underwent pre-operative radiographic assessment, with differing imaging modalities (X-ray and CT), for baseline measurement of deformity. Baseline neurological assessments were also conducted prior to surgery. In Wang’s review of 28 patients, functional neurology screenings were conducted using the American Spinal Injury Association grades (ASIA). In Viswanathan’s group, preoperative neurological deficit was assessed using Frankel grade, with grade A for 2 patients, C for 13 patients, and D for 12 patients. Viswanathan’s series of 95 patients presenting post-vertebrectomy primary or metastatic tumors (75 one-level, 19, two-level, 1 three-level), 23 patients had primary spinal tumors and 72 had metastatic tumors. The patients in this cohort represented 76% of all the patients discussed in the three reviews (n=124). Furthermore, if combined patients from these
- 6. LITERARY REVIEW OF INTERBODY CAGES IN SPINALSURGERY 6 series are included in outcomes and complications, it should be noted that the cohort suffering from malignancy would lower the median morbidity and mortality rate from all cohorts. Although the median survival rate of the metastatic patients was 13.7 months (range 1-102 months), the author, Viswanathan, believes that the surgery actually may have increased anticipated survival. Posterior approach to surgical placement of the interbody spinal cage The posterior approach to spinal corrective surgery has received some attention in the past decade. Although remaining controversial, there are advantages to this approach such as simplification of the initial interbody cage placement, clear neural visualization, and biomechanically, actual correction of coronal deformity. There is also the advantage in the posterior approach in one operation lessens normal risk involved in avoiding further surgeries. Posterior vs. anterior approach or conservative treatment in reduction, decompression and transpedicula stabilization surgery was discussed in all three articles. Kocis’ case study of a 25 year old man with extensive thoracic trauma and burst 5th lumbar was treated with the posterior approach with good results. Kocis is a proponent of the posterior only approach in patients presenting with such injuries and neurological deficit present, although he does state that treatment ultimately depends on the morphology of the fracture and neurological status of the patient. Of the cohort studied by Viswanathan, 15 (15.7%) post-vertebrectomy patients underwent ETC placement from a posterior approach, while the remaining 8 (84.2%) patients underwent the anterior approach. Of these patients, no adverse effects were noted.
- 7. LITERARY REVIEW OF INTERBODY CAGES IN SPINALSURGERY 7 The Wang series examined solely posterior approach with placement of modular anterior cage and posterior segmental fixation in one operation in all 28 of his post-fracture study patients, all with satisfactory outcome. There is still debate as to which is the better spinal surgical treatment: the anterior or posterior approach. More studies need to be conducted in the posterior approach, especially, according to Kocis, in patients presenting burst lumbar fracture with neurological deficits. Clinical safety and performance Out of the three series, the mortality rate <30 days post-operatively was seen in Viswanathan’s cohort where a single patient expired (1.1% of cohort), due to pulmonary embolism. In comparing that with the entire group from the three series, (0.8% of 124 patients from the three studies), the rate is low for mortality. There were major and minor complications found in two groups, both exhibiting similar outcome. The nature of the major complications from both groups are very similar, with one patient from Wang’s group and two patients of Viswanathan’s group (n=3 combined, 2.4% of three cohorts), requiring surgical revision due to hardware failure. One of the patients, a tumor patient, required revision surgery of a suboptimally placed T11 pedicle screw. The second patient, of the same group, underwent surgery for failure of lateral mass instrumentation in a cervico-thoracic construct, following en bloc resection of a chordoma involving C7 and T1. The patient underwent revision surgery without further complication. Of Wang’s cohort, one patient required immediate surgical revision due to cage migration. Radiographic Outcomes Preoperative, immediate postoperative, and the most current radiologic studies conducted during the follow-up periods were used in all articles to determine subsidence, restoration of
- 8. LITERARY REVIEW OF INTERBODY CAGES IN SPINALSURGERY 8 sagittal alignment, and the height correction attained. Differing imagery modalities were often available pre-operatively and post-operatively, including X-ray, MRI, and CT, thus some variable percentages were calculated using normalized values. Viswanathan’s cohort of post- vertebrectomy patients due to primary or metastatic tumor, and Wang’s post vertebral fraction patients scores shall be discussed. In Kocis’s case study of a single patient with a burst L5 vertebra, pre-and postoperative scores were not given in the article, so will not be included. Of the 95 post-vertebrectomy patients in the Viswanathan series, 91 (96%) had evaluable imaging studies. The mean radiographic follow-up interval for the Viswanathan patients was 8.1 months, (range 1-62 months). The Wang article published measurements in subsidence and sagittal alignment during pre-and immediate post-operative points on all 23 patients, with a mean radiographic follow-up period of 31 months, range (12-36 months). Viswanathan reported 94 (99%) of patients were evaluated for initial subsidence of the ETC based on immediate post-operative X-ray or CT; 4 of these patients demonstrated greater than 1 mm of subsidence into either the upper or lower vertebral body. 66 patients, (69%), had CT or X-ray >30 days, postoperatively. Of these 66 patients, 11 (17%) showed greater than 1 mm of subsidence. Of Wang’s group, subsidence was addressed in n=3 (13%) patients at varying time-periods postoperatively. The subsidence values in these 3 patients was 6mm, 8mm, and 12 mm, respectively. It may be noted that these three patients all had burst L-1 or T12 fractures, which may or may not have played a role in this complication. Sagittal alignment correction is a primary concern of this type of surgical intervention. Of the 95 patients in this cohort, there were 90 patients (95%) measured for sagittal alignment from the pre-operative period to immediate post-operative period. Of these 95 patients, there was a mean of 6° (range 0-20°) in improvement at the immediate post-operative time. There were 68
- 9. LITERARY REVIEW OF INTERBODY CAGES IN SPINALSURGERY 9 patients (72%) with sufficient follow-up imaging >30 days postoperatively to determine if the correction in sagittal alignment was durable. In this group, the median sagittal alignment improvement, from preoperative condition, remained 6°, (range 0°-20°). In the series of 23 fracture-patients discussed in the Wang article, radiographic studies of sagittal alignment were measured using the Cobb angle. Values for all patients were given, however, the timeframe of follow-up for these data was not given. The median Cobb angle at the preoperative phase was 26.3. (range 10-45). All patients in this group showed sagittal alignment correction postoperatively in all 23 patients, with a mean Cobb score of 13.3, (range 3-25). The overall mean correction of sagittal alignment in the Wang article was 13.3 (range 0-27). Height correction was available between preoperative and immediate postoperative imaging in 91 patients (96%), with a mean height correction of 14% (range 0-118%) in Viswanathan’s group. Height correction from the Wang series of post-fracture injuries was measured in all patients at the preoperative, postoperative, and at a follow-up beginning at 12 months and ending at 36 months, however actual values pertaining to height correction were not given in the article. Neurological Findings All three studies used neurological deficit as part of their inclusionary criteria, with assessments measured at the pre-and immediately postoperative timeframe, as well as during the various follow-up period of the three studies discussed. It is argued by both Kocis and Wang that the posterior method of surgical intervention is superior compared to the anterior or posterior/anterior approach in patients with neurological deficits. In the Viswanathan series of primary and metastatic tumor patients, the posterior approach was employed in 15 (15.7%) of the patients with the remaining 8 (84.2%) of patients underwent the anterior approach. These data
- 10. LITERARY REVIEW OF INTERBODY CAGES IN SPINALSURGERY 10 do not discuss if the Viswanathan series used the posterior or anterior approach in the patients studied due to neurological indications. Neurological deficit correction, as with other study outcome variables, was published in all three articles at the pre-and postoperative periods and during follow-up, using various scoring instruments. Data from the Wang series were measured utilizing the ASIA Impairment Scale, (Table 1.). Viswanathan used the Frankel scale in his study, whereas Twenty-seven patients (28%) presented preoperatively with neurological deficit. [Frankel grade A (N = 2), C (N = 13) or D (N = 12)]. Postoperatively, one patient with a Frankel grade A was a E at discharge. The remaining 18 patients remained stable. Kocis’s case study of a single patient gives a clinical assessment. His 25 year-old 5th lumbar fracture patient presented at the time of emergency surgery with unspecified neurological deficit. Kocis reported the patient remained stable, = 4 years postoperatively. Postoperative Outcome When discussing any type of surgical procedure, postoperative outcome is probably the most important aspect of any intervention. And, in spinal surgeries, postoperative complications can be severe and varied. However, in reviewing the three articles, the authors appear to be in agreement that the interbody cage is a safe option for the correction of spinal trauma. Of the 124 patients from the three articles combined, postoperative complications overall occurred in 31 (25%) of all patients. The articles showed overlap in the type of complications seen, thus lending some predictability to possible outcome. Of patients reviewed by Viswanathan, 1 (0.8%) patient mortality due to a pulmonary embolism occurred out of the 124 patients reviewed from the three articles combined. This patient, from the post-vertebrectomy tumor group, had an intraoperative durotomy, then
- 11. LITERARY REVIEW OF INTERBODY CAGES IN SPINALSURGERY 11 underwent placement of a lumbar drain. As a preventative measure against CNS fluid leak, she was placed on postoperative bed rest, which may have contributed to the deep venous thrombosis. This is an unfortunate, but routine, complication of any surgery Hardware complications within the first 30 days postoperatively In discussing complications, the three groups of patients, (n=124) shall be combined due to similarity of procedures and outcomes. Hardware failure had one of the lower rates, with 4 (3.2%) of the patients experiencing hardware-related complication, 3 (2.4%) of whom had revision surgery. Indications for revision surgery were primarily due to instrument migration with 2 (1.6%) patients requiring this type of revision. A third patient was also reported as having instrumentation migration, however, she was a metastatic breast cancer patient and did not have revision surgery due to clinical prognosis. 1 (0.8%) patient had instrumentation failure requiring revision to sublaminar wires with no further complications, Overall, the cage-related failures had a low incidence and were found to be safe and durable in these studies. Other postoperative complications The complications not requiring any hardware revision of all patients included 3 (2.4%) patients with postoperative pneumonia, 6 (5%) patients with deep venous thrombosis, 4 (3.2%) patients with cerebrospinal fluid leak, 2 (1.61%) patients with urinary tract infections, 1 (0.8%) patient with a pulmonary embolus, 3 (2.4%) patients with subsidence, 1 (0.8%) patient with wound dehiscence, 1 (0.8%) patient with T6 radiculopathy, and 1 (0.8%) incident of brachial plexopathy. Additionally, 2 (1.6%) patients had postoperative infections requiring operative intervention, often seen as a complication in any type of surgery, but neither required removal of hardware. Both patients were from Wang’s study of the post-fracture group. They recovered completely and without further incident.
- 12. LITERARY REVIEW OF INTERBODY CAGES IN SPINALSURGERY 12 Conclusion Whether trauma or primary/metastatic tumor results in compression or burst fracture, the spine is often placed into kyphosis. The patient presenting such syndrome may experience progressive neurological injury, intractable pain, debilitating physical deformity and can ultimately lead to compromised respiration. Kyphosis is a progressive disease; left untreated, the prognosis is unfavorable. Past treatment, being body casting, bedrest, and bracing, has proven not only intrusive and lending to complication such as pneumonia and thrombosis, but also may be ineffective in many patients in the long-term. Given modern innovation in the management of malignancies, as well as increased life expectancy, long-term, durable, effective treatment is desirable for these patients. In the three articles reviewed, the consensus is corrective surgery using the intervertebral cage is a viable, lasting option for patients with kyphotic spinal deformities. Further study is required to assess the durability of this procedure and approach over time, however, the interbody cage does appear to be an attractive alternative to remedies of the past.
- 13. LITERARY REVIEW OF INTERBODY CAGES IN SPINALSURGERY 13 References Wang, M. (2008). Correlation of Late Traumatic Thoracic and Thoracolumbar Kyphotic Spinal Deformities Using Posteriorly Placed Intervertebral Distraction Cages. Operative Neurosurgery, Pages 79 – 92 Visranthan, A. (2011). Initial experience with the use of an expandable titanium cage as a vertebral body replacement in patients with tumors of the spinal column: a report of 95 patients. European Spine Journal, Pages 84 - 92 Kocis, J. (2008). Complete burst fracture of the fifth lumbar vertebra treated by posterior surgery using expandable cage. Acta Neurochirurgica, Pages 1301 – 1305.
- 14. LITERARY REVIEW OF INTERBODY CAGES IN SPINALSURGERY 14 Table Table 1. Pre- and Postoperative ASIA scores – Wang Article Preoperative score Postoperative Scores Total no. of patients A B C D E A 1 0 0 0 0 1 B 0 1 1 0 0 2 C 0 0 1 4 1 6 D 0 0 0 0 15 15 E 0 0 0 0 4 4 Patient total 1 1 2 4 20 28